1. Technical Field
The present invention relates to a sheet feed unit capable of feeding a sheet-like recording medium, and further relates to an image forming apparatus such as a laser printer, a digital copier, and a facsimile machine including the sheet feed unit.
2. Related Art
A sheet feed unit of an image forming apparatus usually includes a single-step or multi-storied sheet feed tray, in which a plurality of sheet-like recording media can be stored and each sheet feed tray or sheet feed cassette is detachably attached to the main body of the image forming apparatus. The sheet feed tray is normally configured to be inserted into and pulled out from the main body of the image forming apparatus via an opening disposed at one side thereof.
When supplying the sheet or transmitting a print job, it is necessary to confirm whether or not the sheet is stored in the sheet feed tray externally. Recently, various approaches have been tried to enable the remaining paper supply level to be ascertained from outside, and image forming apparatuses including a display that shows a remaining paper supply level have been proposed. For example, JP-H09-2672-A discloses an apparatus including a slit window disposed on a front side wall, through which the number of sheets remaining in the sheet feed tray can be observed directly observed from outside. Alternatively, JP-2007-223689-A discloses an apparatus including a display mechanism, disposed on a cover of the sheet feed tray, to show the remaining paper supply level by contacting a top surface of the sheets inside the sheet feed tray.
Depending on where the image forming apparatus is installed, there may be an obstacle such as a wall in the direction to pull out the sheet feed tray from the main body, thereby obstructing insertion and removal of the sheet feed tray. To cope with the aforementioned problem, JP-H09-221236-A and JP-2005-255363-A propose an image forming apparatus which is configured to install a sheet feed tray in the image forming apparatus main body from two different directions. Even in such an image forming apparatus, however, a display showing a remaining level of the recording media may not be observed from outside or is difficult to be seen depending on the size of the obstacle and a positional relation between the obstacle and the sheet feed tray.